Electric fan harnesses are a beneficial upgrade over the stock clutch fan.
An e-fan harness upgrade will decrease the load on the engine and water pump that will result in increase HP and throttle response.
In addition, an e-fan harness will draw more air across the radiator in stop and go traffic and at idle, which will result in cooler engine temps and cooler AC temperatures in the cab.
We offer two types of e-fan harnesses that are plug and play, with the addition of PCM programming. The PCM programming will be an add on and offered once you check out.
The first type of e-fan harness is for GMT800 99-07 trucks/suv (cbs) equipped with the 28″ radiator. This radiator is in most 1/2 ton GM trucks from 99-07. The radiator is 28″ wide and will only accept the f-body (99-02 camaro and trans am) e-fan assembly.
The e-fan harness is equipped with f-body (ls1) e-fan connectors. Pics are supplied in each type of e-fan assembly to assist in picking the correct e-fan harness.
The second e-fan option is for trucks/suv that are equipped with a 34″ radiator. This radiator is factory installed in most GMT800 2005+ and 2008+ GM trucks/suv. Generally speaking and relating to what is typically accepted on forums, it’s the radiator that is installed on all GMT900 1/2 ton trucks/suv (named nnbs on the internet).
This explanation is why a one pcm pin harness and a two pin pcm harness. (1pin / 2pin) is offered.
– The 99-02 GMT800 (cbs) trucks/suv PCM do not support a high speed AC stage 2 activation. This means the e-fans will activate on low speed based on engine coolant temp (ect) and low ac line pressure. The alternative to high speed e-fan activation ( both e-fans on high speed) is to activate the e-fan relay when the AC clutch is engaged. This is required to maintain acceptable AC pressures during low speed mph.
– The reason why this is implemented is due to the fact that the 99-02 trucks/suv are not equipped with a tertiary high pressure ac sensor. The PCM does not register AC high pressure, which means the PCM cannot activate high speed when AC pressures exceed a certain value.
We do offer an upgrade for the 99-02 trucks that will allow the use of an AC high pressure switch. This means your e-fan operation will function just like a 2005+ PCM.
If you’re deciding on which e-fans to choose, your options are the f-body e-fan assembly and the ’05+ truck e-fan assembly. Keep in mind the use of the vehicle, amount of weight being towed and cost of upgrade.
Note: The HD GM trucks/suv clutch fan will pull/draw more air while towing vs electric fans.
If the vehicle is used for heavy towing then we do not recommend the use of an electric fan unless tow weight is light.